Characterization of a family 11 xylanase fromBacillus subtillisB230 used for paper bleaching

Abstract

Enzymes such as family 11 xylanases are increasingly being used for industrial applications. Here, the cloning, structure determination and temperature-stability data of a family 11 xylanase, Xyn11X, from the alkali-tolerant Bacillus subtilis subspecies B230 are reported. This enzyme, which degrades xylan polymers, is being produced on an industrial scale for use in the paper-bleaching industry. Xyn11X adopts the canonical family 11 xylanase fold. It has a greater abundance of side chain to side chain hydrogen bonds compared with all other family 11 xylanase crystal structures. Means by which the thermostability of Xyn11X might be improved are suggested.

Solution scattering studies of conformation stability of xylanase XYNII from Trichoderma longibrachiatum

“…The earlier reported superpositions 9,[18][19][20]23 were made for increasing the number of solved structures of xylanases 11. Here all available crystal structures of xylanases belonging to family 11 and currently deposited in the Protein Data Bank have been compared and superposed on XYNII molecule to illustrate the stability of the xylanase molecule of family 11.…”

“…9,10 It is worth mentioning that Moiseeva and Allaire 11 have reported on crystallization of this enzyme and its preliminary diffraction studies to a resolution as good as 0.095 nm; however, the structure determined at this resolution has not been published yet in the Protein Data Bank (PDB). Besides the structure of XYNII, several crystal structures of other xylanases from family 11 have been solved by X-ray diffraction, including the enzymes from Aspergillus kawachii, 12 Aspergillus niger, 13 Bacillus agaradhaerens, 14 Bacillus circulans, 15,16 Bacillus D3, 17 Bacillus subtilis B230, 18 Chaetomium thermophilum,…”

Biobleaching of banana fibre pulp using Bacillus subtilis C O1 xylanase produced from wheat bran under solid-state cultivation

“…Several studies have been reported on kraft pulp bleaching with xylanase from diVerent microbial sources, mostly for reducing the amount of chlorine requirement in the bleaching process, kappa number reduction and brightness enhancement [5,9,18,24]. Literature on biobleaching of alternate cellulosic Wbres are scanty.…”

High-Level Heterologous Expression ofBacillus haloduransPutative Xylanase Xyn11A (BH0899) inKluyveromyces lactis

“…14) A significant industrial utility of some family-11 xylanases is in the biobleaching of kraft pulp. [18][19][20][21] We analyzed sugar (total and reducing) and chromophore (absorbing at 237 and 465 nm) release from EKP by rXyn11A, as described by Elegir et al 22) and Wood and Bhat, 14) to validate our TLC result with respect to EKP hydrolysis (Fig. 3).…”